refactor: 상품 좋아요 비정규화

Author: Kimjipang

apps/commerce-api/src/main/java/com/loopers/application/like/LikeFacade.java

@@ -2,6 +2,7 @@
 
 import com.loopers.domain.like.Like;
 import com.loopers.domain.like.LikeRepository;
+import com.loopers.domain.product.Product;
 import com.loopers.domain.product.ProductRepository;
 import com.loopers.domain.user.UserRepository;
 import com.loopers.interfaces.api.like.LikeV1Dto;
@@ -32,7 +33,7 @@ public LikeInfo doLike(LikeV1Dto.LikeRequest request) {
                 () -> new CoreException(ErrorType.NOT_FOUND, "존재하지 않는 유저입니다.")
         );
 
-        productRepository.findById(productId).orElseThrow(
+        Product product = productRepository.findById(productId).orElseThrow(
                 () -> new CoreException(ErrorType.NOT_FOUND, "존재하지 않는 상품입니다.")
         );
 
@@ -42,6 +43,8 @@ public LikeInfo doLike(LikeV1Dto.LikeRequest request) {
                     Like newLike = request.toEntity();
                     likeRepository.save(newLike);
 
+                    product.addLikeCount();
+
                     return LikeInfo.from(newLike);
                 });
     }

apps/commerce-api/src/main/java/com/loopers/application/product/ProductFacade.java

@@ -32,18 +32,15 @@ public ProductInfo registerProduct(ProductV1Dto.ProductRequest request) {
         Product product = request.toEntity();
         productRepository.save(product);
 
-        return ProductInfo.from(product, 0);
+        return ProductInfo.from(product);
     }
 
     @Transactional(readOnly = true)
     public List<ProductInfo> findAllProducts() {
         List<Product> products = productRepository.findAll();
 
         return products.stream()
-                .map(product -> {
-                    int likeCount = likeRepository.countByProductId(product.getId());
-                    return ProductInfo.from(product, likeCount);
-                })
+                .map(ProductInfo::from)
                 .toList();
     }
 
@@ -53,9 +50,7 @@ public ProductInfo findProductById(Long id) {
                 () -> new CoreException(ErrorType.NOT_FOUND, "찾고자 하는 상품이 존재하지 않습니다.")
         );
 
-        int likeCount = likeRepository.countByProductId(id);
-
-        return ProductInfo.from(product, likeCount);
+        return ProductInfo.from(product);
     }
 
     @Transactional(readOnly = true)
@@ -66,10 +61,7 @@ public List<ProductInfo> searchProductsByCondition(ProductV1Dto.SearchProductReq
         List<Product> products = productRepository.searchProductsByCondition(request);
 
         return products.stream()
-                .map(product -> {
-                    int likeCount = likeRepository.countByProductId(product.getId());
-                    return ProductInfo.from(product, likeCount);
-                })
+                .map(ProductInfo::from)
                 .toList();
     }
 }

apps/commerce-api/src/main/java/com/loopers/application/product/ProductInfo.java

@@ -5,14 +5,15 @@
 import java.math.BigDecimal;
 
 public record ProductInfo(Long id, Long brandId, String name, BigDecimal price, int stock, int likeCount) {
-    public static ProductInfo from(Product product, int likeCount) {
+    public static ProductInfo from(Product product) {
         return new ProductInfo(
-            product.getId(),
-            product.getBrandId(),
-            product.getName(),
-            product.getPrice(),
-            product.getStock(),
-            likeCount
+                product.getId(),
+                product.getBrandId(),
+                product.getName(),
+                product.getPrice(),
+                product.getStock(),
+                product.getLikeCount()
         );
+
     }
 }

apps/commerce-api/src/main/java/com/loopers/domain/product/Product.java

@@ -29,20 +29,24 @@ public class Product extends BaseEntity {
     @Column(name = "stock", nullable = false)
     private int stock;
 
+    @Column(name = "like_count", nullable = false)
+    private int likeCount;
 
-    public Product(Long brandId, String name, BigDecimal price, int stock) {
+
+    public Product(Long brandId, String name, BigDecimal price, int stock, int likeCount) {
         this.brandId = brandId;
         this.name = name;
         this.price = price;
         this.stock = stock;
+        this.likeCount = likeCount;
     }
 
     public Product changePrice(BigDecimal newPrice) {
         this.price = newPrice;
         return this;
     }
 
-    public Product decreaseStock(int amount) {
+    public void decreaseStock(int amount) {
         if (amount <= 0) {
             throw new CoreException(ErrorType.BAD_REQUEST, "재고 감소량은 0보다 커야 합니다.");
         }
@@ -51,11 +55,14 @@ public Product decreaseStock(int amount) {
         }
         this.stock -= amount;
 
-        return this;
     }
 
     public boolean isInStock(int quantity) {
         return this.stock >= quantity;
     }
 
+    public int addLikeCount() {
+        return this.likeCount++;
+    }
+
 }

apps/commerce-api/src/main/java/com/loopers/interfaces/api/product/ProductV1Dto.java

@@ -27,7 +27,8 @@ public Product toEntity() {
                     brandId,
                     name,
                     price,
-                    stock
+                    stock,
+                    0
             );
         }
     }